"I consider the Accession Treaty with Croatia to be one of the biggest achievements of our presidency and it was my pleasure to be part of the signing ceremony," Tusk said speaking at a plenary session of the European Parliament which focused on the results of the Polish presidency in the second half of this year.

Tusk said the doors were open to other countries too, to Serbia and Montenegro, although the Polish presidency wanted Serbia to be granted candidate status and Montenegro given a date for the start of the entry talks at a summit on 9 December.

In his speech in the European Parliament, the Polish prime minister strongly advocated European unity, condemning all forms of national egotism. He also addressed some comments which do not hide satisfaction with the fact that Great Britain had rejected the EU deal on fiscal discipline, which was why the EU decided at its summit last week to enter a separate intergovernmental agreement, as consensus was needed to make changes in the Lisbon Treaty. The Polish PM said he did not understand the satisfaction of some by the fact that Great Britain had isolated itself.

The European Union consists of 27 members plus Croatia and not 27 members minus one or minus 10, Tusk stressed.

European Commission President Jose Manuel Barroso said that during its EU presidency, Poland had shown exceptional ability to resolve the key challenges that Europe was facing.